fastga.models.aerodynamics.components.figure_digitization module

Generic class containing all the digitization needed to compute the aerodynamic coefficient of the aircraft.

class fastga.models.aerodynamics.components.figure_digitization.FigureDigitization(**kwargs)

Bases: openmdao.core.explicitcomponent.ExplicitComponent

Provides lift and drag increments due to high-lift devices.

Store some bound methods so we can detect runtime overrides.

static delta_cd_plain_flap(chord_ratio, control_deflection) → float

Roskam data to account for the profile drag increment due to the deployment of plain flap (figure 4.44).

Parameters

• chord_ratio – control surface over lifting surface ratio.

• control_deflection – control surface deflection, in deg.

Return delta_cd_flap

profile drag increment due to the deployment of flaps.

static k_prime_plain_flap(flap_angle, chord_ratio)

Roskam data to estimate the correction factor to estimate non-linear lift behaviour of plain flap (figure 8.13).

Parameters

• flap_angle – the flap angle (in °).

• chord_ratio – flap chord over wing chord ratio.

Return k_prime

correction factor to estimate non-linear lift behaviour of plain flap.

static cl_delta_theory_plain_flap(thickness, chord_ratio)

Roskam data to estimate the theoretical airfoil lift effectiveness of a plain flap ( figure 8.14).

Parameters

• thickness – the airfoil thickness.

• chord_ratio – flap chord over wing chord ratio.

Return cl_delta

theoretical airfoil lift effectiveness of the plain flap.

static k_cl_delta_plain_flap(thickness_ratio, airfoil_lift_coefficient, chord_ratio)

Roskam data to estimate the correction factor to estimate difference from theoretical plain flap lift (figure 8.15).

Parameters

• thickness_ratio – airfoil thickness ratio.

• airfoil_lift_coefficient – the lift coefficient of the airfoil, in rad**-1.

• chord_ratio – flap chord over wing chord ratio.

Return k_cl_delta

correction factor to account for difference from theoretical plain

flap lift.

static k_prime_single_slotted(flap_angle, chord_ratio)

Roskam data to estimate the lift effectiveness of a single slotted flap (figure 8.17), noted here k_prime to match the notation of the plain flap but is written alpha_delta in the book.

Parameters

• flap_angle – the control surface deflection angle (in °).

• chord_ratio – control surface chord over lifting surface chord ratio.

Return k_prime

lift effectiveness factor of a single slotted flap.

static base_max_lift_increment(thickness_ratio: float, flap_type: float) → float

Roskam data to estimate base lift increment used in the computation of flap delta_cl_max (figure 8.31).

Parameters

• thickness_ratio – thickness ratio f the lifting surface, in %.

• flap_type – type of flap used as described in Roskam, for now can be 0.0 for plain,

1.0 for single_slot. :return: delta_cl_base.

static k1_max_lift(chord_ratio, flap_type) → float

Roskam data to correct the base lift increment to account for chord ratio difference wrt to the reference flap configuration (figure 8.32).

Parameters

chord_ratio – ration of the chord of the control surface over that of the whole

surface, in %. :param flap_type: type of flap used as described in Roskam, for now can be 0.0 for plain, 1.0 for single_slot.

Return k1

correction factor to account for chord ratio difference wrt the reference

configuration.

static k2_max_lift(angle, flap_type) → float

Roskam data to correct the base lift increment to account for the control surface deflection angle difference wrt to the reference flap configuration (figure 8.33).

Parameters

• angle – control surface deflection angle, in °.

• flap_type – type of flap used as described in Roskam, for now can be 0.0 for plain,

1.0 for single_slot. :return k2: correction factor to account for the control surface deflection angle wrt the reference configuration.

static k3_max_lift(angle, flap_type) → float

Roskam data for flap motion correction factor (figure 8.34).

Parameters

• angle – control surface deflection angle, in °.

• flap_type – type of flap used as described in Roskam, for now can be 0.0 for plain,

1.0 for single_slot. :return k3: correction factor to account flap motion correction.

static k_b_flaps(eta_in: float, eta_out: float, taper_ratio: float) → float

Roskam data to estimate the flap span factor Kb (figure 8.52) This factor accounts for a finite flap contribution to the 3D lift increase, depending on its position and size and the taper ratio of the wing.

Parameters

• eta_in – position along the wing span of the start of the flaps divided by span.

• eta_out – position along the wing span of the end of the flaps divided by span.

• taper_ratio – taper ration of the surface.

Returns

kb factor contribution to 3D lift.

static a_delta_airfoil(chord_ratio) → float

Roskam data to estimate the two-dimensional flap effectiveness factor (figure 8.53a) This factor can be then used in the computation of the 3D flap effectiveness factor which is often the coefficient of interest.

Parameters

chord_ratio – ration of the chord of the control surface over that of the whole

surface. :return: kb factor contribution to 3D lift.

static k_a_delta(a_delta_airfoil, aspect_ratio) → float

Roskam data to estimate the two-dimensional to three-dimensional control surface lift effectiveness parameter (figure 8.53b).

Parameters

• a_delta_airfoil – control surface two-dimensional flap effectiveness factor.

• aspect_ratio – aspect ratio of the fixed surface.

Return k_a_delta

two-dimensional to three-dimensional control surface lift effectiveness

parameter.

static x_cp_c_prime(flap_chord_ratio: float) → float

Roskam data to estimate the location of the center of pressure due to Incremental Flap Load (figure 8.91).

Parameters

flap_chord_ratio – ratio of the control surface chord over the lifting surface chord.

Return x_cp_c_prime

location of center of pressure due to flap deployment.

static k_p_flaps(taper_ratio, eta_in, eta_out) → float

Roskam data to account for the partial span flaps factor on the pitch moment coefficient (figure 8.105).

Parameters

• taper_ratio – lifting surface taper ratio.

• eta_in – start of the control surface, in percent of the lifting surface span.

• eta_out – end of the control surface, in percent of the lifting surface span.

Return k_p

partial span factor.

static pitch_to_reference_lift(thickness_ratio: float, chord_ratio: float) → float

Roskam data to account for the ratio between the pitch moment coefficient and the reference lift coefficient increment (figure 8.106).

Parameters

• thickness_ratio – thickness to chord ratio of the lifting surface.

• chord_ratio – chord ratio of the control surface over the lifting surface.

Return delta_cm_delta_cl_ref

ration between the pitching moment and the reference lift

coefficient.

static k_delta_flaps(taper_ratio: float, eta_in: float, eta_out: float) → float

Roskam data to estimate the conversion factor which accounts for partial span flaps on a swept wing (c_prime/c = 1.0) (figure 8.107).

Parameters

• taper_ratio – lifting surface taper ratio.

• eta_in – start of the control surface, in percent of the lifting surface span.

• eta_out – end of the control surface, in percent of the lifting surface span.

Return delta_k

partial span factor.

static k_ar_fuselage(taper_ratio, span, avg_fuselage_depth) → float

Roskam data to account for the effect of the fuselage on the VTP effective aspect ratio ( figure 10.14).

Parameters

• taper_ratio – lifting surface taper ratio.

• span – lifting surface span, in m.

• avg_fuselage_depth – average fuselage depth (diameter if fuselage considered

circular), in m. :return k_ar_fuselage: correction factor to account for the end plate effect of the fuselage

on effective VTP AR.

static k_vh(area_ratio) → float

Roskam data to estimate the impact of relative area ratio on the effective aspect ratio ( figure 10.16).

Parameters

area_ratio – ratio of the horizontal tail area over the vertical tail area.

Return k_vh

impact of area ratio on effective aspect ratio.

static k_ch_alpha(thickness_ratio, airfoil_lift_coefficient, chord_ratio)

Roskam data to compute the correction factor to differentiate the 2D control surface hinge moment derivative. due to AOA from the reference (figure 10.63).

Parameters

• thickness_ratio – airfoil thickness ratio.

• airfoil_lift_coefficient – the lift coefficient of the airfoil, in rad**-1.

• chord_ratio – flap chord over wing chord ratio.

Return k_ch_alpha

correction factor for 2D control surface hinge moment derivative due to

AOA.

static ch_alpha_th(thickness_ratio, chord_ratio)

Roskam data to compute the theoretical 2D control surface hinge moment derivative due to AOA (figure 10.63).

Parameters

• thickness_ratio – airfoil thickness ratio.

• chord_ratio – flap chord over wing chord ratio.

Return ch_alpha

theoretical hinge moment derivative due to AOA.

static k_ch_delta(thickness_ratio, airfoil_lift_coefficient, chord_ratio)

Roskam data to compute the correction factor to differentiate the 2D control surface hinge moment derivative due to control surface deflection from the reference (figure 10.69 a).

Parameters

• thickness_ratio – airfoil thickness ratio.

• airfoil_lift_coefficient – the lift coefficient of the airfoil, in rad**-1.

• chord_ratio – control surface chord over lifting surface chord ratio.

Return k_ch_delta

hinge moment derivative due to control surface deflection correction

factor.

static ch_delta_th(thickness_ratio, chord_ratio)

Roskam data to compute the theoretical 2D control surface hinge moment derivative due to control surface deflection (figure 10.69 b).

Parameters

• thickness_ratio – airfoil thickness ratio.

• chord_ratio – flap chord over wing chord ratio.

Return ch_delta

theoretical hinge moment derivative due to control surface deflection.

static k_fus(root_quarter_chord_position_ratio) → float

Roskam data to estimate the empirical pitching moment factor K_fus (figure 16.14).

Parameters

root_quarter_chord_position_ratio – the position of the root quarter chord of the

wing from the nose. divided by the total length of the fuselage. :return k_fus: the empirical pitching moment factor.

static cl_beta_sweep_contribution(taper_ratio, aspect_ratio, sweep_50) → float

Roskam data to estimate the contribution to the roll moment of the sweep angle of the lifting surface. (figure 10.20)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

• sweep_50 – the sweep angle at 50 percent of the chord of the lifting surface, in deg

Return cl_beta_lambda

the contribution to the roll moment of the sweep angle of the

lifting surface.

static cl_beta_sweep_compressibility_correction(swept_aspect_ratio, swept_mach) → float

Roskam data to estimate the compressibility correction for the sweep angle. (figure 10.21)

Parameters

• swept_aspect_ratio – the aspect ratio of the lifting surface divided by cos(sweep_50)

• swept_mach – mach number multiplied by cos(sweep_50)

Return k_m_lambda

compressibility correction for the sweep angle.

static cl_beta_fuselage_correction(swept_aspect_ratio, lf_to_b_ratio) → float

Roskam data to estimate the fuselage correction factor. (figure 10.22)

Parameters

• swept_aspect_ratio – the aspect ratio of the lifting surface divided by cos(sweep_50)

• lf_to_b_ratio – ratio between the distance from nose to root half chord and the

wing span :return k_fuselage: fuselage correction factor.

static cl_beta_ar_contribution(taper_ratio, aspect_ratio) → float

Roskam data to estimate the contribution to the roll moment of the aspect ratio of the lifting surface. (figure 10.23)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

Return cl_beta_ar

the contribution to the roll moment of the aspect ratio of the

lifting surface.

static cl_beta_dihedral_contribution(taper_ratio, aspect_ratio, sweep_50) → float

Roskam data to estimate the contribution to the roll moment of the dihedral angle of the lifting surface. (figure 10.24)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

• sweep_50 – the sweep angle at 50 percent of the chord of the lifting surface, in deg

Return cl_beta_gamma

the contribution to the roll moment of the dihedral angle of the

lifting surface.

static cl_beta_dihedral_compressibility_correction(swept_aspect_ratio, swept_mach) → float

Roskam data to estimate the compressibility correction for the dihedral angle. (figure 10.25)

Parameters

• swept_aspect_ratio – the aspect ratio of the lifting surface divided by cos(sweep_50)

• swept_mach – mach number multiplied by cos(sweep_50)

Return k_m_gamma

compressibility correction for the dihedral angle.

static cl_beta_twist_correction(taper_ratio, aspect_ratio) → float

Roskam data to estimate the correction due to the twist of the lifting surface. (figure 10.26)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

Return k_epsilon

the factor to take into account the twist of the lifting surface for

the computation of the rolling moment

static cl_p_roll_damping_parameter(taper_ratio, aspect_ratio, mach, sweep_25, k) → float

Roskam data to estimate the contribution to the roll moment of the roll damping parameter (figure 10.35).

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

• mach – the mach number

• sweep_25 – the sweep angle at 25 percent of the chord of the lifting surface, in deg

• k – the ratio between the airfoil slope and 2*np.pi

Return k_roll_damping

the roll damping parameter

static cl_p_cdi_roll_damping(sweep_25, aspect_ratio) → float

Roskam data to estimate the contribution to the roll moment damping of the drag-due-to-lift (figure 10.36)

Parameters

• sweep_25 – the sweep angle at 25% of the chord of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

Return k_cdi_roll_damping

the contribution to the roll moment of the aspect ratio of the

lifting surface.

static cl_r_lifting_effect(aspect_ratio, taper_ratio, sweep_25)

Roskam data to estimate the slope of the rolling moment due to yaw rate (figure 10.41). The figure is separated into two parts (a and b).

Parameters

• aspect_ratio – wing aspect ratio

• taper_ratio – wing taper ratio

• sweep_25 – wing sweep angle at quarter-taper point line in radians

Return cl_r_lift

slope of the rolling moment due to yaw rate

static cl_r_twist_effect(taper_ratio, aspect_ratio) → float

Roskam data to estimate the contribution to the roll moment coefficient of the twist. (figure 10.42)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

Return k_twist

contribution to the roll moment coefficient of the twist.

static cn_delta_a_correlation_constant(taper_ratio, aspect_ratio, eta_i) → float

Roskam data to estimate the correlation constant for the computation of the yaw moment due to aileron. (figure 10.48)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

• eta_i – aileron inboard span location, as a ratio of the span

Return k_a

the correlation constant for the computation of the yaw moment

due to aileron

static cn_p_twist_contribution(taper_ratio, aspect_ratio) → float

Roskam data to estimate the contribution to the yaw moment of the twist of the lifting surface. (figure 10.37)

Parameters

• taper_ratio – the taper ratio of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

Return cn_p_twist

the contribution to the yaw moment of the twist of the

lifting surface.

static cn_r_lift_effect(static_margin, sweep_25, aspect_ratio, taper_ratio) → float

Roskam data to estimate the effect of lift for the computation of the yaw moment due yaw rate (yaw damping). (figure 10.48)

Parameters

• static_margin – distance between aft cg and aircraft aerodynamic center divided by MAC

• sweep_25 – the sweep at 25% of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

• taper_ratio – the taper ratio of the lifting surface

Return lift_effect

the effect of lift fot the computation of the yaw moment due to yaw

rate

static cn_r_drag_effect(static_margin, sweep_25, aspect_ratio) → float

Roskam data to estimate the effect of drag for the computation of the yaw moment due yaw rate (yaw damping). (figure 10.48)

Parameters

• static_margin – distance between aft cg and aircraft aerodynamic center divided by MAC

• sweep_25 – the sweep at 25% of the lifting surface

• aspect_ratio – the aspect ratio of the lifting surface

Return drag_effect

the effect of drag for the computation of the yaw moment due to yaw

rate

fastga.models.aerodynamics.components.figure_digitization.interpolate_database(database, tag_x: str, tag_y: str, input_x: float)

Utility to interpolate the data csv.

fastga.models.aerodynamics.components.figure_digitization.filter_nans(database: pandas.core.frame.DataFrame, tags: List[str]) → List[numpy.ndarray]

Utility function to jointly filter out NaN in the database with the selected tags.